1. Field of the Invention
The present invention relates to a printing technology of an ink jet printer. More specifically, the present invention relates to an ink set, a treating liquid, a recording liquid, an image recording apparatus, and an image recording method.
2. Description of Related Art
An image recording method carrying out an image recording with a recording liquid (containing a coloring material) as a droplet is excellent in that a printing mechanism thereof is simple and that the method is free from noise.
On the other hand, however, the above image recording method in combination with some record media may cause an image defect typical example thereof including a feathering, thus greatly decreasing an image quality. In terms of the above problem, suppressing permeability of the recording liquid is being tried for decreasing the feathering. Suppressing the permeability, however, may deteriorate dryness of the recording liquid, thus adhering the recording liquid to a hand when the hand touches a printed matter after printing, or smearing the image, which is another problem.
Printing a color image may superimpose one after another the recording liquids with different colors, thus bleeding or mixing the color ink on a color boundary, resulting in a greatly decreased image quality. For decreasing the color bleeding, the permeability of the recording liquid is tried to be increased. Increasing the recording liquid, however, may cause the coloring material to enter the record medium, thus decreasing the image density and increasing permeation of the recording liquid to backside of the record medium. With this, a both-side print may not be carried out preferably.
The image recording method is desired to solve the above problems at the same time and increase the image quality.
With respect to the above problems, methods of combining the recording liquid with a treating liquid are proposed, where the treating liquid contains a component that can form an aggregate with a coloring material in the recording liquid.
Japanese Patent (JP-B) No. 2675001 discloses a method of using, as a treating liquid, a liquid that is a colorless or hypochromic and contains polyvalent metal compound. Japanese Patent Application Laid-Open (JP-A) No. 2002-332438 discloses a method of using a treating liquid containing fine-particles in a dispersed state, where the fine-particles have a surface which is so charged as to have different polarity from that of a recording liquid. JP-A No. 2002-332438 is, however, not sufficient in terms of image quality. Especially, the liquid containing, in the dispersed state, the reactive fine particles can be added by a greater amount of reactive components by suppressing liquid viscosity increase, compared with the treating liquid of Japanese Patent (JP-B) No. 2675001 which dissolves the polyvalent metal compound. Compared with the polyvalent metal compound and the like, the above fine particles are larger in nature, thereby may form a large aggregate when the dispersed state is collapsed by the reaction of the fine particle with the coloring material. As a result, a great viscosity increase may occur, and thereby may suppress fluidity of the coloring material, thus improving the image by preventing the feathering and the like.
In the printing method of reacting two liquids (recording liquid and treating liquid) on the record medium, the lower the surface tension of the treating liquid is, the more widely the treating liquid spreads near the surface of the recording medium. With this, the treating liquid may become better in terms of embedding to the surface of the record medium, thereby the coloring material of the recording liquid may more stay on the surface of paper, thus improving the image including such properties as image density, back-through density and chroma. The treating liquid having lower surface tension may spread more widely. With this, even a small amount of treating liquid is sufficient for suppressing the permeation (caused by the aggregate reaction) of the recording liquid into the record medium, resulting in decreased total amount of liquid, thereby decreasing problems such as the feathering, the color bleeding and cockling.
The treating liquid having the low surface tension of less than 35 mN/m may, as a matter of fact, cause bubble in the loading of the treating liquid to a nozzle head, thus frequently causing discharge failure attributable to the bubble. With this, it may become difficult to secure discharge stability of all the nozzles, disenabling to stably produce the high-quality-image printed matter.
It is an object of the present invention to provide an ink set including a recording liquid and a treating liquid capable of obtaining a high-quality-image printed matter.
It is another object of the present invention to provide the ink set where the component and property of the treating liquid and the recording liquid are adjusted, moreover a combination of the component and the property is adjusted.
It is still another object of the present invention to provide an image recording apparatus and an image recording method using the ink set.